The present invention relates to communications in computer networks. More specifically, it relates to a method for dynamically changing the type-of-service with an associated quality-of-service between network devices such as a cable modem and another network device.
Cable television networks such as those provided by Comcast Cable Communications, Inc., of Philadelphia, Pa., Cox Communications of Atlanta Ga., Tele-Communications, Inc., of Englewood Colo., Time-Warner Cable, of Marietta Ga., Continental Cablevision, Inc., of Boston Mass., and others provide cable television services to a large number of subscribers over a large geographical area. The cable television networks typically are interconnected by cables such as coaxial cables or a Hybrid Fiber/Coaxial (xe2x80x9cHFCxe2x80x9d) cable system which have data rates of about 10 Megabits per second (xe2x80x9cMbpsxe2x80x9d) to 30+ Megabits per second.
The Internet, a world-wide-network of interconnected computers, provides multi-media content including audio, video, graphics and text that typically requires a large bandwidth for downloading and viewing. Most Internet Service Providers (xe2x80x9cISPsxe2x80x9d) allow customers to connect to the Internet via a serial telephone line from a Public Switched Telephone Network (xe2x80x9cPSTNxe2x80x9d) at data rates including 14,400 bits per second, 28,800 bits per second, 33,600 bits per second, 56,000 bits per second and others that are much slower than the about 10 Megabits per second to 30+ Megabits per second available on a coxial cable or hybrid fiber/coaxial cable system on a cable television network.
With the explosive growth of the Internet, many customers have desired to use the larger bandwidth of a cable television network to connect to the Internet and other computer networks. Cable modems, such as those provided by 3Com Corporation of Santa Clara, Calif., U.S. Robotics Corporation of Skokie, Ill., and others offer customers higher-speed connectivity to the Internet, an intranet, Local Area Networks (xe2x80x9cLANsxe2x80x9d) and other computer networks via cable television networks. These cable modems currently support a data connection to the Internet and other computer networks via a cable television network with a xe2x80x9cdownstreamxe2x80x9d data rate of 30+ Megabits per second, which is a much larger data rate than what can be supported by serial telephone line used over a modem.
However, most cable television networks provide only uni-directional cable systems, supporting only a xe2x80x9cdownstreamxe2x80x9d data path. A downstream data path is the flow of data from a cable system xe2x80x9cheadendxe2x80x9d to a customer. A cable system headend is a central location in the cable television network that is responsible for sending cable signals in the downstream direction. A return data path via a telephone network, such as a Public Switched Telephone Network provided by ATandT and others, (i.e., xe2x80x9ctelephony returnxe2x80x9d) is typically used for an xe2x80x9cupstreamxe2x80x9d data path. An upstream data path is the flow of data from the customer back to the cable system headend. A cable television system with an upstream connection to a telephony network is called a xe2x80x9cdata-over-cable system with telephony return.xe2x80x9d In a two-way cable system without telephony return, the customer premise equipment sends response data packets to the cable modem, which sends the data packets upstream via the cable television network to the cable modem termination system. The cable modem termination system sends the response data packets back to the appropriate host on the data network.
An exemplary data-over-cable system with telephony return includes a cable modem termination system, a cable television network, a public switched telephone network, a telephony remote access concentrator, a cable modem, customer premise equipment (e.g., a customer computer) and a data network (e.g., the Internet). The cable modem termination system and the telephony remote access concentrator together are called a xe2x80x9ctelephony return termination system.xe2x80x9d
The cable modem termination system receives data packets from the data network and transmits them downstream via the cable television network to a cable modem attached to the customer premise equipment. The customer premise equipment sends responses data packets to the cable modem, which sends response data packets upstream via the public switched telephone network to the telephony remote access concentrator, which sends the response data packets back to the appropriate host on the data network. The data-over-cable system with telephony return provides transparent Internet Protocol (xe2x80x9cIPxe2x80x9d) data traffic between customer premise equipment, a cable modem and the data network (e.g., the Internet or an intranet). As is known in the art, Internet Protocol is a routing protocol designed to route traffic within a network or between networks.
When a cable modem used in the data-over-cable system with telephony return is initialized, it will make a connection to both the cable modem termination system via the cable network and to the telephony remote access concentrator via the public switched telephone network. If the cable modem is using telephony return, it will acquire telephony connection parameters on a downstream connection from the cable modem termination system and establish a Point-to-Point Protocol (xe2x80x9cPPPxe2x80x9d) connection to connect an upstream channel to the telephony remote access concentrator. As is known in the art, point-to-point protocol is used to encapsulate datagrams over a serial communications link. After a point-to-point protocol connection is established, the cable modem negotiates a telephony Internet protocol address with the telephony remote access concentrator. The telephony Internet Protocol address allows the customer premise equipment to send Internet Protocol data packets upstream to the telephony remote access concentrator via the public switched telephone network to the data network.
The cable modem also makes an IP connection to the cable modem termination system so that Internet Protocol data received on the cable modem termination system from the data network can be forwarded downstream to the customer premise equipment via the cable network and the cable modem.
Once an Internet Protocol address is obtained on the cable modem termination system, the cable modem obtains the name of a configuration file used to complete initialization. The cable modem downloads a configuration file from a central location in the data-over-cable system using a Trivial File Transfer Protocol (xe2x80x9cTFTPxe2x80x9d) server. As is known in the art, trivial file transfer Protocol is a very simple protocol used to transfer files, where any error during file transfer typically causes a termination of the file transfer.
There are several problems associated with using a configuration file from a central location to configure a cable modem. In a typical cable modem initialization scenario, a Dynamic Host Configuration Protocol (xe2x80x9cDHCPxe2x80x9d) is used to obtain an Internet Protocol address and the name of a configuration file on a Dynamic Host Configuration Protocol server from which configuration parameters, including type-of-service (xe2x80x9cToSxe2x80x9d), are assigned for the cable modem. The configuration file is downloaded from the Dynamic Host Configuration Protocol server to the cable modem with trivial file transfer protocol using a trivial file transfer protocol server. Each Dynamic Host Configuration Protocol server has an identical copy of the same configuration file. Therefore, each cable modem in the data-over-cable system is configured with the same way with the same configuration file containing specific type-of-service parameters. Further, a cable modem in the data-over-cable system does not have an opportunity to select a different type-of-service associated with a different quality-of-service than that statically assigned in the configuration file.
Since all cable modems in the data-over-cable are not made by the same manufacturer and may be used for a number of different purposes by a variety of end users, a single common configuration file with default or statically assigned type-of-service parameters is inappropriate for all cable modems in the data-over-cable system. Furthermore, the user of a cable modem may desire to use a particular type-of-service associated with an associated quality-of-service other than that assigned by the configuration file. By allowing a user to change the default type-of-service, the user may select a type-of-service not supported by the cable modem, but one that is needed to perform a particular application or feature on the data-over-cable system. Although the cable modem may not support the type-of-service selected, the cable modem may allow the user to perform the application or to use the desired feature and provide the appearance of the selected type-of-service.
For a Dynamic Host Configuration Protocol server to provide multiple types-of-service in lieu of a single, default type-of-service, each Dynamic Host Configuration Protocol server would be required to maintain more than one configuration file. Furthermore, the Dynamic Host Configuration Protocol server may communicate with the cable modem to request the type-of-service desired. In this scenario, the Dynamic Host Configuration Protocol server may not only maintain a listing of configuration files for each particular type-of-service possible, but also provide a communications step not currently supported by Dynamic Host Configuration Protocol the first type-of-service to the requested second type-of-service with an associated second quality-of-service. Thus, the first network device may dynamically change a statically assigned first type-of-service from a common configuration file to a different, second type-of-service with an associated second quality-of-service.
In accordance with a preferred embodiment of the present invention, the first network device is a cable modem and the second network device is a cable modem termination system. Furthermore, the first network device can be a cable modem termination system and the second can be a cable modem. The first network device receives a selection input in the form of a message requesting a specific type-of-service.
In a preferred embodiment of the present invention, a cable modem accepts a first type-of-service provided by the Dynamic Host Configuration Protocol server in the common configuration file. However, when a cable modem receives a selection input requesting a second type-of-service, the cable modem may dynamically change the statically assigned, first type-of-service to a second type-of-service with an associated second quality-of-service.
A preferred embodiment of the present invention allows a cable modem to dynamically change a statically assigned, first type-of-service provided by a common, default configuration file to a requested, second type-of-service. If the second type-of-service is a permitted type-of-service for the particular cable modem in the data-over-cable system, the cable modem termination system will apply the second type-of-service even though the cable modem may not support the second type-of-service. However, if the second type-of-service is not permitted for the particular cable modem, the cable modem termination system may continue to use the first type-of-service provided in the common, default configuration file. This provides flexibility for servers. This is not practical in a data-over-cable system. In addition, modifying Dynamic Host Configuration Protocol servers to use more than one configuration file violates the spirit of the Dynamic Host Configuration Protocol standard and is cost prohibitive due to the large number of Dynamic Host Configuration Protocol servers including third party Dynamic Host Configuration Protocol servers in the data-over-cable system that would require modifications.
Therefore, it is desirable to allow an individual cable modem to dynamically change the type-of-servers from a statically assigned type-of-service provided in a common default configuration file without modifying existing Dynamic Host Configuration Protocol servers or the Dynamic Host Configuration Protocol initialization process used to obtain the configuration file.
In accordance with a preferred embodiment of the present invention, the problems associated with initializing a cable modem using default configuration parameters from a common configuration file are overcome. A method is provided for changing a default, first type-of-service with an associated first quality-of-service statically assigned by a common configuration file to a different, second type-of-service with an associated second quality-of-service.
The method includes monitoring a connection between a first network device and a second network device. Once the first network device has established a connection with the second network device, the first network device receives a configuration file from the second network device which contains statically assigned configuration parameters. One such parameter is a first type-of-service with an associated first quality-of-service. The first network device receives a selection input requesting a second type-of-service. The first network device changes users on the date-over-cable system without modifying Dynamic Host Configuration Protocol servers or the Dynamic Host Configuration Protocol initialization process.
The foregoing and other features and advantages of a preferred embodiment of the present invention will be more readily apparent from the following detailed description, which proceeds with references to the accompanying drawings.